Federal fisheries experts are painting a devastating picture of the challenges facing Pacific salmon and point to climate change as the main culprit.

Andrew Thompson, regional director for fisheries management, says it’s been an extremely challenging year for salmon and there have been significant declines in a number of stocks.

He says the trend is also being seen in waters off Alaska and Washington state.

Fisheries staff say factors such as human activity that degrades fish habitat and a landslide on the Fraser River blocking millions of fish from spawning upstream are making things worse.

In one of the most dramatic shifts, the federal Department of Fisheries has adjusted the number of returning Fraser River sockeye to slightly more than 600,000, down from an earlier projection of nearly five million.

Sue Grant, head of a federal program on the state of salmon, says some of the declines are residual effects of larger climate change events.

“Everything we’re seeing in salmon and ecosystem trends is embedded within this larger context,” she said.

“The planet is warming and the most recent five years have been the warmest on the planet’s record,” she said, adding that Canada is warming at a rate double the global average and the rate increases at northern latitudes.

Climate events like “The Blob,” an enormous mass of warm water caused by a heat wave in the North Pacific, have had significant impacts on the food web, she said.

It prompted large fatty zooplankton, the primary food of Pacific salmon, to migrate north and be replaced by a much smaller, less nutritious species of plankton.